Construction of Longitudinal (003) Textured Low-Strain Diffusion Channel in 4.6 V LiCoO₂-Based All-Solid-State Thin Film Battery for Microelectronic Systems

The growing trend of unmanned monitoring and the widespread popularity of intelligent automation necessitate higher energy storage for self-powered microbatteries. All-solid-state thin-film lithium batteries offer significant advantages in size and integration but are still subject to their low-voltage plateau (<3.3 V) and microampere-level capacity (≤0.2 mWh). Herein, we proposed the crystal-facet engineering combined with the substrate anchoring effect to address critical structure variation in the 4.6 V LiCoO2 film. The rotated (003) basal plane effectively relieves internal stress and the Li+ migration energy barrier, contributing to strengthened continuous migration channels and a structure skeleton in Nb2O5@LCO nanosheets. Therefore, the additive-free full cell exhibits excellent cyclability, retains 72.5% capacity retention over 500 cycles at 1.4 C between 3.0 and 4.6 V, and has a high energy density of 1.148 mWh cm–2 in a 3.5 cm2 thin-film cell. This study provides a prototype method for tailoring desired compatible thin film electrode materials for further on-chip microdevices.